Flamboyant Australian billionaire Clive Palmer on Thursday said he plans to sue Rupert Murdoch over unflattering allegations and claimed the media mogul's estranged wife is a Chinese spy.

Palmer, best known for building a replica of the Titanic and who is running for election in Australia on Saturday, seethed over a comment piece questioning his wealth and whether he was indeed a university professor and a mining magnate, as he claims.

Murdoch's flagship The Australian ran the story on its front page under the headline "Why we need to worry about the real Mr Palmer", alleging he was "a man with a history of peddling fantasies that often morph into a unique version of 'reality'".

According to the latest polls, the Palmer United Party is on track to win a Senate seat in his home state of Queensland and the daily said it would allow him to "exert his unsubtle influence in Canberra".

"Contrary to the flim-flam and spin, Clive Frederick Palmer is not a professor, not an adviser to the G20, not a mining magnate, not a legal guru and not an advocate for freedom of speech. He's probably not a billionaire," the newspaper said.

The broadsheet is backing conservative opposition leader Tony Abbott to win the election and said it had spent months examining Palmer's track record.

Palmer, who says he has made his money in mining and is also a real estate developer and tourism resort operator, was a long-time supporter of Abbott's Liberal-National coalition. He tore up his membership last year after a bitter, public dispute and set up his own party.

He accused Australian-born Murdoch, now a US citizen, of telling his reporters what to write and said he needed to be brought to account.

"Murdoch will be sued by me today and will be brought to Australia to answer these questions in the Supreme Court," he told the Seven Network.

"It's time this fellow was brought to account, this foreigner who tries to dictate what we do."

In a separate interview with the Nine Network, Palmer made extraordinary claims about Murdoch's estranged wife Wendi Deng.

"'You know, Rupert Murdoch's wife Wendi Deng is a Chinese spy, and that's been right across the world,'' Palmer alleged, prompting the stunned host to ask whether he had "lost the plot".

"She's been spying on Rupert for years, giving money back to Chinese intelligence. She was trained in southern China. I'm telling you the truth," Palmer said.

"Wendi Deng is a Chinese spy and that's why Rupert got rid of her."

He continued: "And this guy (Murdoch) wants to control Australian politics. He wants to control what you think."

The Palmer United Party is fielding candidates in each of the 150 seats in the House of Representatives and 18 Senate candidates across the eight states and territories as it spreads its populist message, which includes slashing taxation.

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